On the recordApril 10, 2013
the reason why it is in the national interest of the United States is because, No. 1, we do not want our allies, our strong allies, in the region, Israel, Jordan, Turkey, et cetera, to feel threatened by this; No. 2, because we do not want there to be created an unstable environment that can be used as a staging ground for attacks against the United States, both at home and around the world; and No. 3, because it is a nation awash with very dangerous weapons, and those weapons can be transferred to all sorts of bad actors around the world to be used against our interests.
Source
congress.gov
